(a) Field
The described technology relates generally to a frame transmitting method and a frame receiving method. More particularly, the described technology relates generally to a frame transmitting method and a frame receiving method in a wireless local area network (WLAN).
(b) Description of the Related Art
A WLAN is being standardized by the IEEE (Institute of Electrical and Electronics Engineers) Part 11 under the name of “Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications.”
After an original standard was published in 1999, new version standards are continuously published by amendments. The IEEE standard 802.11a (IEEE Std 802.11a-1999) supporting 2.4 GHz band was published in 1999, the IEEE standard 802.11b (IEEE Std 802.11b-1999) supporting 5 GHz band was published in 1999, and the IEEE standard 802.11g (IEEE Std 802.11g-2003) supporting 5 GHz band was published in 2003. These standards are called legacy. Subsequently, the IEEE standard 802.11n (IEEE Std 802.11n-2009) for enhancements for higher throughput (HT) was published in 2009, and the IEEE standard 802.11 ac (IEEE 802.11 ac-2013) for enhancements for very high throughput (VHT) was published in 2013. Recently, a high efficiency (HE) WLAN for enhancing the system throughput in high density scenarios is being developed by the IEEE 802.11ax task group.
The HE WLAN or a subsequent WLAN may use a multi-user transmission. For example, a device may simultaneously transmit data to a plurality of devices or the plurality of devices may simultaneously transmit data by using a scheme such as orthogonal frequency division multiple access (OFDMA).
For the multi-user transmission, a given bandwidth may be divided into a plurality of subbands and the plurality of bands may be allocated to multi users. In this case, since a resource unit used in the subband is different from a resource unit used in a previous version WLAN, hardware of a previous version WLAN device cannot be reused.